The slogan ARBEIT MACHT FREI over the gate translates as "Work (shall) make (you) free" (or "work liberates"). Auschwitz is the name used to identify three main Nazi German concentration camps and 45-50 sub-camps. It’s situated about 60 km southwest of Cracow. Beginning in 1940, Nazi Germany built several concentration camps and an extremination camps in the area, which at the time had been annexed by Nazi Germany. The camps were a major constituent of the Holocaust.

• Auschwitz I, the original concentration camp which served as the administrative centre for the whole complex, and was the site of the deaths of roughly 70,000 Polish intellectuals and Soviet Prisoners of War
  
• Auschwitz II (Birkenau), an extermination camp and the site of the deaths of roughly 1 million Jews, 75,000 Poles and 19,000 Roams
  
• Auschwitz III (Monowitz), which served as a labor camp for the IG Farben company
  

The total number of casualties is still under debate, but most modern estimates are around 1-1.5 million.
Like all Nazi concentration camps, the Auschwitz camps were operated by Heinricht Himmler's SS. The commandants of the camp were the SS-Obersturmbannführers Rudolf Höß (sometimes transliterated in English as "Hoess") until Summer 1943, and later Arthur Liebehenschel and Richard Baer. Höß provided a detailed description of the camp's workings during his interrogations after the war and also in his autobiography. He was hanged in 1947 in front of the entrance to the crematorium of Auschwitz I.

About 700 prisoners attempted to escape from the Auschwitz camps during the years of their operation, with about 300 attempts successful. A common punishment for escape attempts was death by starvation; the families of successful escapees were sometimes arrested and interned in Auschwitz and prominently displayed to deter others.

The Polish government then decided to restore Auschwitz I and turn it into a museum honoring the victims of Nazism; Auschwitz II, where buildings were prone to decay, was preserved but not restored. Today, the Auschwitz I museum site combines elements from several periods into a single complex: for example the gas chamber at Auschwitz I (which did not exist by the war's end) was restored and the fence was moved (because of building being done after the war but before the establishment of the museum). However, in most cases the departure from the historical truth is minor, and is mentioned as such.

Auschwitz II and the remains of the gas chambers there are also open to the public. The Auschwitz concentration camp is part of the UNESCO list of World Heritage Sites.

In 1979, the newly elected Polish pope John Paul II celebrated Mass on the grounds of Auschwitz II to some 500,000 people. After the pope had announced that Edith Stein would be beatified, some Catholics erected a cross near bunker 2 of Auschwitz II where she had been gassed. A short while later, a Star of David appeared at the site, leading to a proliferation of religious symbols there; eventually they were removed.